class Datadog::OpenTelemetry::SDK::Propagator

def extract(
  carrier, context: ::OpenTelemetry::Context.current,
  getter: ::OpenTelemetry::Context::Propagation.text_map_getter
)
  unless getter == ::OpenTelemetry::Context::Propagation.text_map_getter
    Datadog.logger.error(
      'Custom getter is not supported. Please inform the `ddtrace` team at ' \
    ' https://github.com/DataDog/dd-trace-rb of your use case so we can best support you. Using the default ' \
    'OpenTelemetry::Context::Propagation.text_map_getter as a fallback getter.'
    )
  end
  digest = @datadog_propagator.extract(carrier)
  return context unless digest
  trace_id = to_otel_id(digest.trace_id)
  span_id = to_otel_id(digest.span_id)
  if digest.trace_state || digest.trace_flags
    trace_flags = ::OpenTelemetry::Trace::TraceFlags.from_byte(digest.trace_flags)
    tracestate = Tracing::Distributed::TraceContext.new(fetcher: nil).send(:build_tracestate, digest)
  else
    trace_flags = if Tracing::Sampling::PrioritySampler.sampled?(digest.trace_sampling_priority)
                    ::OpenTelemetry::Trace::TraceFlags::SAMPLED
                  else
                    ::OpenTelemetry::Trace::TraceFlags::DEFAULT
                  end
    tracestate = ::OpenTelemetry::Trace::Tracestate::DEFAULT
  end
  span_context = ::OpenTelemetry::Trace::SpanContext.new(
    trace_id: trace_id,
    span_id: span_id,
    trace_flags: trace_flags,
    tracestate: tracestate,
    remote: true
  )
  span = ::OpenTelemetry::Trace.non_recording_span(span_context)
  trace = Tracing.continue_trace!(digest)
  span.datadog_trace = trace
  ::OpenTelemetry::Trace.context_with_span(span, parent_context: context)
end

def fields
  []
end

def initialize(datadog_propagator)
  @datadog_propagator = datadog_propagator
end

def inject(
  carrier, context: ::OpenTelemetry::Context.current,
  setter: ::OpenTelemetry::Context::Propagation.text_map_setter
)
  unless setter == ::OpenTelemetry::Context::Propagation.text_map_setter
    Datadog.logger.error(
      'Custom setter is not supported. Please inform the `ddtrace` team at ' \
    ' https://github.com/DataDog/dd-trace-rb of your use case so we can best support you. Using the default ' \
    'OpenTelemetry::Context::Propagation.text_map_setter as a fallback setter.'
    )
  end
  @datadog_propagator.inject!(context.trace.to_digest, carrier)
end

def to_otel_id(dd_id)
  Array(dd_id).pack('Q')
end